If anyone wants a YAG rod, I think I have a few various sizes lying around I could sell, but as Chad and Mike say, its not as simple as shining a light on it. You need to set up a resonator cavity, which ain't really too if you happen to have a couple thousand dollar optical table and another couple thousand dollars of mounts and optics laying around, an insane degree of patience, and something to view the IR and verify your work. That would perhaps get you a setup for pulsed operation. For CW, then you have cooling concerns to add in to. So all in all - not anything less than an "expert" level type of DIY project, and though I'm not horrible I know I sure don't consider myself an expert at laser DIY.
BTW, this seller seems a bit shifty. Got negative FB for nondelivery - has Stan in his name, and the account was registered around when the scammer Stan Turecki took a break from his laserprogram account. Could just be a coincidence - his auctions aren't quite like those of laserprogram, but it gets my paranoid self a little nervous :-/